Mist eliminators are typically employed to remove liquid mist or liquid particles from a gas stream in which liquid has been suspended or entrained. Mist eliminators may be employed in a wide variety of devices where there are gas-liquid contacts and are particularly used for the cleaning of waste or flue gas streams in a wet scrubber or other applications. In such processes, mist eliminator devices are provided in one or more layers across a gas-liquid contacting column or duct to remove the mist from the gas to provide a mist-lean gas stream from a mist-rich gas stream.
Mist eliminators may comprise a wide variety of different structures; however, one very popular type of mist eliminator comprises a baffle-type or chevron-type mist eliminator which is arranged in one or more layers and provides for a zigzag or a tortuous flow path through the generally parallel, spaced-apart, mist eliminator baffles, with the baffles generally having an upstream and a downstream edge and arranged horizontally within the gas-liquid column or chamber, although they may assume other sloped positions, and vertical positions.
These baffle-type mist eliminators are designed so that the liquid droplets may be collected and not re-entrained during the passage through the mist eliminator, so that the design of the proper mist eliminator is a function of a number of variables, such as, but not limited to, the design and geometry of the gas flow path through the mist eliminator, the nature of the gas stream, temperatures, velocities and amount and droplet size of the liquid.
One illustrated example of a chevron-type mist eliminator and method is described, for example, in U.S. Pat. No. 4,601,731, issued Jul. 22, 1986. This mist eliminator, as described, is employed in a gas-liquid column with a layer composed of a plurality of parallel, spaced-apart serpentine baffles, extending across the upwardly flowing gas path, defining therebetween a plurality of tortuous gas flow paths. The baffles are presented substantially angularly to the axis of the column and have surfaces for the impingement of the upwardly flowing mist-rich gas stream to provide for liquid collection, and includes downwardly projecting drainage points on the leading edge of the baffles to promote the rapid drainage of the baffles. The chevron-type baffles employed provide for a change in direction of the gas flow path at an angle of about 45.degree., generally at least four times in each mist eliminator layer.
It is desirable to provide for a new and improved chevron or baffle-type mist eliminator-system containing such mist eliminators and a method of removing liquids in gas-rich streams, particularly where higher gas throughputs are desired to pass through the mist-eliminator device before collected liquid is re-entrained in the gas stream, such as, but not limited to, wet scrubbing process towers of large diameter.